THE LARGEST ever international study of mobile phone safety has concluded the devices do not raise the risk of brain cancer, except possibly a slight increase in tumours among the most intensive users.
The telecoms industry, which contributed $6 million (€5m) to the $24 million Interphone study through an “arm’s length” funding mechanism, said the findings, published yesterday, supported its view that mobile phones were safe. But the industry said it was prepared to support more research.
Critics said the flawed methodology of the study concealed a more worrying increase in glioma, the most deadly brain tumour, in the heaviest mobile users – defined as people who have used mobile phones for more than 1,640 hours. WiredChild, a UK pressure group, said implications for children, who were not included in the Interphone study, were serious.
Scientists in 13 countries carried out the study under the auspices of the International Agency for Research on Cancer, part of the World Health Organisation. They interviewed 5,100 brain cancer patients and a similar number of matched “controls”, who did not have cancer, about their mobile phone use.
Although data collection ended in 2004, publication of the study was delayed while the researchers argued about how best to present their results. It eventually appeared yesterday in the International Journal of Epidemiology.
A particular issue was the finding that regular mobile users had less brain cancer than non-users matched for sex, age and social background, though there is no biologically plausible way phones could protect against tumours.
When the results are adjusted to correct for this apparent flaw in the study method there is a larger increase in cancer risk among the most intense mobile users.
“An increased risk of brain cancer is not established from the data from Interphone,” said Dr Christopher Wild, IARC director, summing up the study. “However, observations at the highest level of cumulative call time and changing patterns of mobile phone use since the period studied by Interphone, particularly in young people, mean that further investigation of mobile phone use and brain cancer risk is merited.”
The leaders of the study in the UK, Professors Anthony Swerdlow of the Institute of Cancer Research and Patricia McKinney of Leeds University, were more dismissive of any causal link between mobile phone use and brain cancer.
They said the apparent association in intense users was probably a false finding because of the study method. Some glioma patients reported improbable levels of mobile use, said Prof Swerdlow, averaging more than 12 hours a day over a year. The European Union is organising an investigation of the risk to children from using mobiles. – (Copyright The Financial Times Limited 2010)